I recently fried a rs pro by reversing the polarity on a lipo. (don't ask)

I had a ballistic on it when the magic smoke appeared.

The motor seemed fine for about 10 batteries, then it seized on me in the middle of an a main.

I replaced the bearings, but it now feels gutless.

I have changed the motor out in the same system and the redline is working fine.

. I'm 100% sure the problem is in the motor.
S
Any ideas where to start looking at what I've done to the motor?

Overheating a motor will kill it. The rotor loses its magnetism and starts to get slow. Overheating will also affect the windings and possibly shorting them out.

Another area is the sensor board.

Would you change out the rotor, or should I send it back to have it refurbished. I just don't want to keep throwing $30 parts into it trying and diagnose the problem myself.